Matt Berry is a brilliant British actor, responsible for the characters of Steven Toast and Laszlo Cravensworth (amongst others). I’ve specifically chosen those two characters in particular, as the way that Matt speaks as them is the funniest thing I have heard for a long time!
It is a British accent, almost RP, performed with a deep and mellifluous tone. It’s almost a standard accent, but for the pronunciation of certain words. Words like “sexual” are accentuated to brilliant comedic effect.
I guess you have to hear it to understand it, but I would love to be able to talk like those characters. Would have brought some much needed frivolity to many a boring meeting.